B72 — Snake Nebula
Dark Nebula in Ophiuchus
About
The Snake Nebula, a dark lane of dust in Ophiuchus about 650 light-years away, shaped like an S. It appears dark because it blocks the stars behind it, and it sits at the north-northwest edge of the Pipe Nebula's bowl.
Imaging tips
- Sources give 37 by 17′ and 20 by 15′; the dust lane itself is only 2–3′ thick and about 6′ long, so a long focal length isolates the S shape.
- One imager used a 784 mm refractor, a modified DSLR, a CLS filter and 7 × 8 minutes at ISO 1600, in a 97 by 65′ field that also held B68.
- Another imager shot LRGB at 1.17″ per pixel; a strong sky-brightness gradient hurt the result, and a reshoot under darker skies was planned.
- Wikipedia says a 4- to 6-inch telescope shows it only under clear, dark skies; use broadband, since a dark nebula has no light of its own.
- Best in May and June; it peaks near 16° altitude from 50°N.
Facts
- Size
- 30′ × 15′
- Magnitude
- —
- Coordinates
- RA 17h 23.6m, Dec −23° 42′
- Framing, APS-C
- 810–1350 mm
- Framing, full frame
- 1240–2060 mm
- Best months
- May, Jun
- Peak altitude
- 16° from 50°N, 31° from 35°N
Nearby
- B68 (Black Cloud) · 16.1′ away